There is a continuing need to identify protective and/or functional coatings in many areas of emerging technologies. For example, most light emitting diodes (LEDs) and solar panels use an encapsulant coating to protect photovoltaic cells from environmental factors. Such protective coatings must be optically clear to ensure maximum efficiency of these devices. Furthermore, these protective coatings must also be tough, durable, long lasting, and yet easy to apply. Various silicone based compositions are known in the art as protective coatings in various electronics and solar devices since silicones are known for their durability.
Many of the silicone compositions used to provide protective electronic coatings today rely on cure mechanisms that require a catalyst in the product compositions. For example, platinum metal catalyzed cure of a silicone composition containing an alkenyl functional organopolysiloxane and an organohydrogensiloxane are very prevalent in the art. However, the subsequent coatings resulting from these hydrosilylation cured systems still have trace amounts of catalyst remaining in the final product. Furthermore, the cure chemistry requires a certain amount of hydrocarbon groups be present on the siloxane polymers. Both the residual catalyst, and presence of hydrocarbon crosslinks may limit the thermal stability and/or long term durability of such coatings.
Thus, there is a need to identify silicone based encapsulants that are optically clear while remaining tough and durable. In particular, there is a need to identify such silicone based coatings that provide convenience of use in the manufacture of various electronic or lighting devices. Ideally, the silicone composition should be considered to be “reprocessable”, in that an initial coating can reflow around device architectures at an elevated processing temperature. Also, the coatings or other solid materials may be initially formed from a silicone composition having certain physical properties, but possess sufficient reactivity to further cure at elevated temperatures to provide coatings with another set of physical properties.